Manjoo was born in South Africa, which he left when he was eight years old.[4] He graduated from Cornell University in 2000. While there, he was a writer and editor-in-chief of the Cornell Daily Sun student newspaper.

He wrote for Wired News before taking a staff position at Salon.com. In July 2008, Manjoo accepted a job at Slate magazine writing a twice-weekly technology column. In September 2013, Manjoo joined the Wall Street Journal as a technology columnist;[1] his final column for Slate, in which he urged men to wear makeup, was published on September 20.[5]